(x+1)+(x+3)+...+(x+99)=1000

=>50x+1+3+...+99=1000

=>50x+\(\dfrac{\left(99-1\right):2+1\cdot\left(1+99\right)}{2}\)=1000

=>50x+2500=1000

=>50x=1000-2500=-1500

=>x=-1500:50=-30.

\(\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+...+\left(x+99\right)=1000\)

\(\left(x+x+x+...+x\right)+\left(1+3+5+7+9+...+99\right)\)

\(\left(x.50\right)+2500\)=1000

\(x.50=1000-2500\)

\(x.50=-1500\)

\(x=-1500:50=-30\)

$\left(x+1\right)+\left(x+3\right)+\left(x+5\right)+...+\left(x+99\right)=1000$

$\left(x+x+x+...+x\right)+\left(1+3+5+7+9+...+99\right)$

$\left(x.50\right)+2500$=1000

$x.50=1000-2500$

$x.50=-1500$

$x=-1500:50=-30$

x=1000-99

x=901

chúc bạn hok tố nhé! hihi

X + 99 = 1000

   X = 1000 - 99

   X = 901

x + 99 = 1000

x        =  1000 - 99

x        = 901

k cho mình nha

a=\(\frac{1}{9}\)

c=\(\frac{3069}{500}\)

= 98/45-31/15

=1/9

[(x+1000):20.2]-1=99

=>(x+1000):10=99+1

=>x+1000=100.10

=>x=1000-1000

=>x=0

vậy x=0

(x+1000) : 20 x 2 = 100

=> (x+1000) : 20 = 50

=> x+1000 = 1000

=> x = 0

Ngu Người đăng cho zui 

bai toan @gmail.com

(1-1/97) x (1-1/98) x (1-1/99) x (1-1/1000) = 96/97 x 97/98 x 98/99 x 999/1000 

= 96 x 97 x 98 x 999 / 97 x 98 x 99 x 1000 = 12 x 111 / 11 x 125 = 1332 / 1375

\(C=\left(1-\frac{1}{97}\right).\left(1-\frac{1}{98}\right).\left(1-\frac{1}{99}\right)......\left(1-\frac{1}{1000}\right)\)

\(C=\frac{96}{97}.\frac{97}{98}.\frac{98}{99}........\frac{999}{1000}\)

\(C=\frac{96}{1000}\)

\(C=\frac{12}{125}\)

ket quả bằng 12 phần 125

toán lớp 7 khó quá

Bằng 2,5 = \(\frac{2500}{1000}\)= \(\frac{25}{10}\) nhé

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